Date: Sat, 11 Dec 2021 10:38:00 +0000 From: David Chisnall <theraven@FreeBSD.org> To: "dmilith ." <dmilith@gmail.com> Cc: "beepc.ch" <xpetrl@beepc.ch>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: Benchmarks: FreeBSD 13 vs. NetBSD 9.2 vs. OpenBSD 7 vs. DragonFlyBSD 6 vs. Linux Message-ID: <B53325BE-AEF5-4FD0-B791-93D3205CCEA4@FreeBSD.org> In-Reply-To: <CAJQ5JnhpioiO_j-iidk8QbfONU6a2Jm%2BunGCdAuN=Es8UZUQzw@mail.gmail.com> References: <CA%2BGLnbgVGghYAYPbQfu0H0cGvXxk-v0jAZTxLLz%2BhRn5eXjP0g@mail.gmail.com> <f8e569a4-3510-5a91-62b2-f9080b197ebc@beepc.ch> <CAJQ5JnhpioiO_j-iidk8QbfONU6a2Jm%2BunGCdAuN=Es8UZUQzw@mail.gmail.com>
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While I agree on most of your points, the value of Phoronix is that it = tests the default install. As an end user, I don=E2=80=99t care that a particular program is twice = as fast on a particular Linux distro as it is on FreeBSD because of = kernel features, compiler options, or dependency choices. I would love to see the base system include the ThinLTO (LLVM IR) .a = files so that I can do inlining from libc into my program. I would love = for ports to default to ThinLTO unless they break with it. Apple = flipped that switch a few years ago, so a lot of things that broke with = ThinLTO are now fixed. The FreeBSD memcpy / memset implementations look like they=E2=80=99re = slower than the latest ones, which can give a 5-10% perf boost on some = workloads. LLVM just landed the automemcpy framework, which is designed = by some Google folks to synthesises efficient memcpy implementations = tailored to different workloads. FreeBSD often wins versus glibc-based distros because jemalloc is faster = than dlmalloc (the default malloc implementations in FreeBSD libc and = glibc, respectively). I=E2=80=99ve been using snmalloc in my libc for a = while and it generally gives me a few percent more perf. Unfortunately, = FreeBSD decided to expose all of the jemalloc non-standard functions = from libc, which means I can=E2=80=99t contribute it to upstream without = implementing all of those on top of snmalloc or it would be an ABI = break. It would be great if someone could pick up the Phronix benchmark suite = and do some profiling: where is FreeBSD spending more time than Linux? = Are there Linux-specific code paths that hit slow paths on FreeBSD and = fast paths on Linux that could have FreeBSD-specific fast paths added = (e.g. futex vs _umtx_op)? David > On 11 Dec 2021, at 10:17, dmilith . <dmilith@gmail.com> wrote: >=20 > 1. Where are compiler options for BSDs? > 2. Why they compare -O2 to -O3 code in some benchmarks? Why they = enable > fast math in some, and disable it for others? > 3. Why they don't mention powerd setup for FreeBSD? By default it may = use > slowest CPU mode. Did they even load cpufreq kernel module? > 4. Did they even care about default FreeBSD mitigations (via sysctl) > enabled, or it's only valid for Linuxes? ;) > 5. What happened to security and environment details of BSDs? >=20 > It's kinda known that guys from Phroenix lack basic knowledge of how = to do > proper performance testing and lack basic knowledge about BSD systems. > Nothing new. Would take these results with a grain of salt. >=20 > On Sat, 11 Dec 2021 at 10:53, beepc.ch <xpetrl@beepc.ch> wrote: >=20 >>> I am surprised to see that the BSD cluster today has much worse >> performance >>> than Linux. >>> What do you think of this? >>=20 >> "Default" FreeBSD install setting are quite conservative. >> The Linux common distros are high tuned, those benchmark is in my >> opinion comparison of apples and oranges. >>=20 >> Comparing "default" FreeBSD install with "default" Slackware install >> would be more interesting, because Slackware builds are at most = vanilla. >>=20 >>=20 >=20 > --=20 > Daniel Dettlaff > Versatile Knowledge Systems > verknowsys.com
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